Add new vhost-user protocol message
`VHOST_USER_BACKEND_SHARED_OBJECT`. This new
message is sent from vhost-user back-ends
to interact with the virtio-dmabuf table
in order to add, remove, or lookup for
virtio dma-buf shared objects.
The action taken in the front-end depends
on the type stored in the payload struct.
In the libvhost-user library add helper
functions to allow sending messages to
interact with the virtio shared objects
hash table.
Signed-off-by: Albert Esteve <aest...@redhat.com>
---
docs/interop/vhost-user.rst | 15 ++++
hw/virtio/vhost-user.c | 68 ++++++++++++++++++
subprojects/libvhost-user/libvhost-user.c | 88 +++++++++++++++++++++++
subprojects/libvhost-user/libvhost-user.h | 56 +++++++++++++++
4 files changed, 227 insertions(+)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 5a070adbc1..d3d8db41e5 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -1528,6 +1528,21 @@ is sent by the front-end.
The state.num field is currently reserved and must be set to 0.
+``VHOST_USER_BACKEND_SHARED_OBJECT``
+ :id: 6
+ :equivalent ioctl: N/A
+ :request payload: ``struct VhostUserShared``
+ :reply payload: ``struct VhostUserShared`` (only for ``LOOKUP`` requests)
+
+ Backends that need to interact with the virtio-dmabuf shared table API
+ can send this message. The operation is determined by the ``type`` member
+ of the payload struct. The valid values for the operation type are
+ ``VHOST_SHARED_OBJECT_*`` members, i.e., ``ADD``, ``LOOKUP``, and ``REMOVE``.
+ ``LOOKUP`` operations require the ``VHOST_USER_NEED_REPLY_MASK`` flag to be
+ set by the back-end, and the front-end will then send the dma-buf fd as
+ a response if the UUID matches an object in the table, or a negative value
+ otherwise.
+
.. _reply_ack:
VHOST_USER_PROTOCOL_F_REPLY_ACK
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 74a2a28663..5ac5f0eafd 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -10,6 +10,7 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "hw/virtio/virtio-dmabuf.h"
#include "hw/virtio/vhost.h"
#include "hw/virtio/vhost-user.h"
#include "hw/virtio/vhost-backend.h"
@@ -20,6 +21,7 @@
#include "sysemu/kvm.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
+#include "qemu/uuid.h"
#include "qemu/sockets.h"
#include "sysemu/runstate.h"
#include "sysemu/cryptodev.h"
@@ -128,6 +130,7 @@ typedef enum VhostUserSlaveRequest {
VHOST_USER_BACKEND_IOTLB_MSG = 1,
VHOST_USER_BACKEND_CONFIG_CHANGE_MSG = 2,
VHOST_USER_BACKEND_VRING_HOST_NOTIFIER_MSG = 3,
+ VHOST_USER_BACKEND_SHARED_OBJECT = 6,
VHOST_USER_BACKEND_MAX
} VhostUserSlaveRequest;
@@ -190,6 +193,18 @@ typedef struct VhostUserInflight {
uint16_t queue_size;
} VhostUserInflight;
+typedef enum VhostUserSharedType {
+ VHOST_SHARED_OBJECT_ADD = 0,
+ VHOST_SHARED_OBJECT_LOOKUP,
+ VHOST_SHARED_OBJECT_REMOVE,
+} VhostUserSharedType;
+
+typedef struct VhostUserShared {
+ unsigned char uuid[16];
+ VhostUserSharedType type;
+ int dmabuf_fd;
+} VhostUserShared;
+
typedef struct {
VhostUserRequest request;
@@ -214,6 +229,7 @@ typedef union {
VhostUserCryptoSession session;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserShared object;
} VhostUserPayload;
typedef struct VhostUserMsg {
@@ -1582,6 +1598,52 @@ static int
vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev,
return 0;
}
+static int vhost_user_backend_handle_shared_object(VhostUserShared *object)
+{
+ QemuUUID uuid;
+ memcpy(uuid.data, object->uuid, sizeof(object->uuid));
+
+ switch (object->type) {
+ case VHOST_SHARED_OBJECT_ADD:
+ return virtio_add_dmabuf(&uuid, object->dmabuf_fd);
+ case VHOST_SHARED_OBJECT_LOOKUP:
+ object->dmabuf_fd = virtio_lookup_dmabuf(&uuid);
+ if (object->dmabuf_fd < 0) {
+ return object->dmabuf_fd;
+ }
+ break;
+ case VHOST_SHARED_OBJECT_REMOVE:
+ return virtio_remove_resource(&uuid);
+ }
+
+ return 0;
+}
+
+static bool
+vhost_user_backend_send_dmabuf_fd(QIOChannel *ioc, VhostUserHeader *hdr,
+ VhostUserPayload *payload)
+{
+ Error *local_err = NULL;
+ struct iovec iov[2];
+ if (hdr->flags & VHOST_USER_NEED_REPLY_MASK) {
+ hdr->flags &= ~VHOST_USER_NEED_REPLY_MASK;
+ hdr->flags |= VHOST_USER_REPLY_MASK;
+
+ hdr->size = sizeof(payload->object);
+
+ iov[0].iov_base = hdr;
+ iov[0].iov_len = VHOST_USER_HDR_SIZE;
+ iov[1].iov_base = payload;
+ iov[1].iov_len = hdr->size;
+
+ if (qio_channel_writev_all(ioc, iov, ARRAY_SIZE(iov), &local_err)) {
+ error_report_err(local_err);
+ return false;
+ }
+ }
+ return true;
+}
+
static void close_slave_channel(struct vhost_user *u)
{
g_source_destroy(u->slave_src);
@@ -1639,6 +1701,12 @@ static gboolean slave_read(QIOChannel *ioc, GIOCondition
condition,
ret = vhost_user_slave_handle_vring_host_notifier(dev, &payload.area,
fd ? fd[0] : -1);
break;
+ case VHOST_USER_BACKEND_SHARED_OBJECT:
+ ret = vhost_user_backend_handle_shared_object(&payload.object);
+ if (!vhost_user_backend_send_dmabuf_fd(ioc, &hdr, &payload)) {
+ goto err;
+ }
+ break;
default:
error_report("Received unexpected msg type: %d.", hdr.request);
ret = -EINVAL;
diff --git a/subprojects/libvhost-user/libvhost-user.c
b/subprojects/libvhost-user/libvhost-user.c
index 8fb61e2df2..27f16d292a 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -1403,6 +1403,94 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq,
int fd,
return vu_process_message_reply(dev, &vmsg);
}
+bool
+vu_get_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN], int *dmabuf_fd)
+{
+ bool result = false;
+ VhostUserMsg msg_reply;
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION | VHOST_USER_NEED_REPLY_MASK,
+ .payload.object = {
+ .type = VHOST_SHARED_OBJECT_LOOKUP,
+ },
+ };
+
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ pthread_mutex_lock(&dev->slave_mutex);
+ if (!vu_message_write(dev, dev->slave_fd, &msg)) {
+ goto out;
+ }
+
+ if (!vu_message_read_default(dev, dev->slave_fd, &msg_reply)) {
+ goto out;
+ }
+
+ if (msg_reply.request != msg.request) {
+ DPRINT("Received unexpected msg type. Expected %d, received %d",
+ msg.request, msg_reply.request);
+ goto out;
+ }
+
+ *dmabuf_fd = msg_reply.payload.object.dmabuf_fd;
+ result = *dmabuf_fd > 0;
+out:
+ pthread_mutex_unlock(&dev->slave_mutex);
+
+ return result;
+}
+
+static bool
+vu_send_message(VuDev *dev, VhostUserMsg *vmsg)
+{
+ bool result = false;
+ pthread_mutex_lock(&dev->slave_mutex);
+ if (!vu_message_write(dev, dev->slave_fd, vmsg)) {
+ goto out;
+ }
+
+ result = true;
+out:
+ pthread_mutex_unlock(&dev->slave_mutex);
+
+ return result;
+}
+
+bool
+vu_add_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN], int dmabuf_fd)
+{
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION,
+ .payload.object = {
+ .dmabuf_fd = dmabuf_fd,
+ .type = VHOST_SHARED_OBJECT_ADD,
+ },
+ };
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ return vu_send_message(dev, &msg);
+}
+
+bool
+vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN])
+{
+ VhostUserMsg msg = {
+ .request = VHOST_USER_BACKEND_SHARED_OBJECT,
+ .size = sizeof(msg.payload.object),
+ .flags = VHOST_USER_VERSION,
+ .payload.object = {
+ .type = VHOST_SHARED_OBJECT_REMOVE,
+ },
+ };
+ memcpy(msg.payload.object.uuid, uuid, sizeof(uuid[0]) * UUID_LEN);
+
+ return vu_send_message(dev, &msg);
+}
+
static bool
vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
{
diff --git a/subprojects/libvhost-user/libvhost-user.h
b/subprojects/libvhost-user/libvhost-user.h
index 49208cceaa..a43d115bd7 100644
--- a/subprojects/libvhost-user/libvhost-user.h
+++ b/subprojects/libvhost-user/libvhost-user.h
@@ -119,6 +119,7 @@ typedef enum VhostUserSlaveRequest {
VHOST_USER_BACKEND_VRING_HOST_NOTIFIER_MSG = 3,
VHOST_USER_BACKEND_VRING_CALL = 4,
VHOST_USER_BACKEND_VRING_ERR = 5,
+ VHOST_USER_BACKEND_SHARED_OBJECT = 6,
VHOST_USER_BACKEND_MAX
} VhostUserSlaveRequest;
@@ -172,6 +173,20 @@ typedef struct VhostUserInflight {
uint16_t queue_size;
} VhostUserInflight;
+typedef enum VhostUserSharedType {
+ VHOST_SHARED_OBJECT_ADD = 0,
+ VHOST_SHARED_OBJECT_LOOKUP,
+ VHOST_SHARED_OBJECT_REMOVE,
+} VhostUserSharedType;
+
+#define UUID_LEN 16
+
+typedef struct VhostUserShared {
+ unsigned char uuid[UUID_LEN];
+ VhostUserSharedType type;
+ int dmabuf_fd;
+} VhostUserShared;
+
#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__))
# define VU_PACKED __attribute__((gcc_struct, packed))
#else
@@ -199,6 +214,7 @@ typedef struct VhostUserMsg {
VhostUserConfig config;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserShared object;
} payload;
int fds[VHOST_MEMORY_BASELINE_NREGIONS];
@@ -539,6 +555,46 @@ void vu_set_queue_handler(VuDev *dev, VuVirtq *vq,
bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd,
int size, int offset);
+/**
+ * vu_get_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ * @dmabuf_fd: output dma-buf file descriptor
+ *
+ * Lookup for a virtio shared object (i.e., dma-buf fd) associated with the
+ * received UUID. Result, if found, is stored in the dmabuf_fd argument.
+ *
+ * Returns: whether the virtio object was found.
+ */
+bool vu_get_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN],
+ int *dmabuf_fd);
+
+/**
+ * vu_add_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ * @dmabuf_fd: output dma-buf file descriptor
+ *
+ * Stores a new shared object (i.e., dma-buf fd) in the hash table, and
+ * associates it with the received UUID.
+ *
+ * Returns: TRUE on success, FALSE on failure.
+ */
+bool vu_add_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN],
+ int dmabuf_fd);
+
+/**
+ * vu_rm_shared_object:
+ * @dev: a VuDev context
+ * @uuid: UUID of the shared object
+ *
+ * Removes a shared object (i.e., dma-buf fd) associated with the
+ * received UUID from the hash table.
+ *
+ * Returns: TRUE on success, FALSE on failure.
+ */
+bool vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]);
+
/**
* vu_queue_set_notification:
* @dev: a VuDev context
--
2.40.0
